How to extract table names and column names from sql query in python?

How to extract table names and column names from sql query in python?

To extract table names and column names from an SQL query in Python, you can use a combination of regular expressions and parsing libraries like sqlparse. Here's a step-by-step guide:

  • Install Dependencies: First, you'll need to install the sqlparse library if you haven't already. This library helps with parsing SQL queries.
pip install sqlparse
  • Python Script:
import sqlparse

def extract_table_and_columns(query):
    # Parse the SQL query
    parsed = sqlparse.parse(query)[0]
    
    tables = []
    columns = []
    
    # Extract tables and columns
    for token in parsed.tokens:
        if isinstance(token, sqlparse.sql.IdentifierList):
            for identifier in token.get_identifiers():
                if "." in identifier.get_real_name():
                    # It's a column (table.column)
                    columns.append(identifier.get_real_name())
                else:
                    # It's a table
                    tables.append(identifier.get_real_name())
    
    return tables, columns

def main():
    sql_query = """
    SELECT users.id, users.name, orders.order_id, orders.order_date
    FROM users
    JOIN orders ON users.id = orders.user_id
    WHERE users.country = 'USA';
    """
    
    tables, columns = extract_table_and_columns(sql_query)
    
    print("Tables:")
    print(tables)
    
    print("\nColumns:")
    print(columns)

if __name__ == "__main__":
    main()

This script defines a function extract_table_and_columns(query) that takes an SQL query as input and returns two lists: one containing table names and another containing column names.

It uses sqlparse to tokenize and parse the SQL query. It iterates through the tokens and identifies whether a token is a table or column based on the presence of a dot (.) in the identifier name.

Note: Parsing SQL queries can be complex due to the variety of query structures and database-specific syntax. This example provides a simple approach that works for basic cases. For more complex queries or specific database dialects, additional parsing and handling may be needed.

Keep in mind that this approach might not cover all edge cases and database-specific syntax, but it should work for many common scenarios.

Examples

  1. How to extract table names and column names from a SQL query string in Python using regular expressions?

    Description: This query focuses on using regular expressions to parse and extract table names and column names from a given SQL query string in Python.

    import re

def extract_tables_and_columns(sql_query):
    table_names = re.findall(r'FROM\s+(\w+)', sql_query, re.IGNORECASE)
    column_names = re.findall(r'SELECT\s+([\w, ]+)', sql_query, re.IGNORECASE)
    return table_names, column_names

sql_query = "SELECT column1, column2 FROM table1 WHERE condition"
table_names, column_names = extract_tables_and_columns(sql_query)
print("Table Names:", table_names)
print("Column Names:", column_names)

  2. How to extract table names and column names from a SQL query using SQL parsing libraries in Python?

    Description: This query is about using SQL parsing libraries like sqlparse to parse and extract table names and column names from a given SQL query string in Python.

    import sqlparse

def extract_tables_and_columns(sql_query):
    parsed_query = sqlparse.parse(sql_query)[0]
    table_names = [token.value for token in parsed_query.tokens if token.ttype == sqlparse.tokens.Name]
    column_names = [token.value for token in parsed_query.tokens if token.ttype == sqlparse.tokens.Name]
    return table_names, column_names

sql_query = "SELECT column1, column2 FROM table1 WHERE condition"
table_names, column_names = extract_tables_and_columns(sql_query)
print("Table Names:", table_names)
print("Column Names:", column_names)

  3. How to extract table names and column names from a SQL query using SQLAlchemy in Python?

    Description: This query focuses on using SQLAlchemy, an ORM (Object Relational Mapper) library, to extract table names and column names from a given SQL query string in Python.

    from sqlalchemy.sql import text

def extract_tables_and_columns(sql_query):
    parsed_query = text(sql_query)
    table_names = parsed_query.bind.table_names()
    column_names = parsed_query.columns.keys()
    return table_names, column_names

sql_query = "SELECT column1, column2 FROM table1 WHERE condition"
table_names, column_names = extract_tables_and_columns(sql_query)
print("Table Names:", table_names)
print("Column Names:", column_names)

  4. How to extract table names and column names from a SQL query using Pandas in Python?

    Description: This query is about using the Pandas library to read a SQL query into a DataFrame and then extract table names and column names.

    import pandas as pd

def extract_tables_and_columns(sql_query):
    df = pd.read_sql_query(sql_query, connection)
    table_names = df.columns
    column_names = df.columns
    return table_names, column_names

sql_query = "SELECT column1, column2 FROM table1 WHERE condition"
table_names, column_names = extract_tables_and_columns(sql_query)
print("Table Names:", table_names)
print("Column Names:", column_names)

  5. How to extract table names and column names from a SQL query using regex and manual parsing in Python?

    Description: This query focuses on using a combination of regex and manual parsing techniques to extract table names and column names from a given SQL query string in Python.

    import re

def extract_tables_and_columns(sql_query):
    table_names = re.findall(r'FROM\s+([\w_]+)', sql_query, re.IGNORECASE)
    column_names = re.findall(r'SELECT\s+(.+?)\s+FROM', sql_query, re.IGNORECASE)[0].split(',')
    return table_names, column_names

sql_query = "SELECT column1, column2 FROM table1 WHERE condition"
table_names, column_names = extract_tables_and_columns(sql_query)
print("Table Names:", table_names)
print("Column Names:", column_names)

  6. How to extract table names and column names from a SQL query using the sql-metadata library in Python?

    Description: This query is about using the sql-metadata library to parse and extract table names and column names from a given SQL query string in Python.

    from sql_metadata import Parser

def extract_tables_and_columns(sql_query):
    parser = Parser(sql_query)
    table_names = parser.tables
    column_names = parser.columns
    return table_names, column_names

sql_query = "SELECT column1, column2 FROM table1 WHERE condition"
table_names, column_names = extract_tables_and_columns(sql_query)
print("Table Names:", table_names)
print("Column Names:", column_names)

  7. How to extract table names and column names from a SQL query using the Spark SQL API in PySpark in Python?

    Description: This query focuses on using the Spark SQL API in PySpark to extract table names and column names from a given SQL query string in Python.

    from pyspark.sql import SparkSession

spark = SparkSession.builder \
    .appName("SQL Extraction") \
    .getOrCreate()

def extract_tables_and_columns(sql_query):
    df = spark.sql(sql_query)
    table_names = df.columns
    column_names = df.columns
    return table_names, column_names

sql_query = "SELECT column1, column2 FROM table1 WHERE condition"
table_names, column_names = extract_tables_and_columns(sql_query)
print("Table Names:", table_names)
print("Column Names:", column_names)

  8. How to extract table names and column names from a SQL query using the ibis library in Python?

    Description: This query is about using the ibis library to extract table names and column names from a given SQL query string in Python.

    import ibis

def extract_tables_and_columns(sql_query):
    client = ibis.sqlite.connect(':memory:')
    table = client.sql(sql_query)
    table_names = table.op().tables()
    column_names = table.columns
    return table_names, column_names

sql_query = "SELECT column1, column2 FROM table1 WHERE condition"
table_names, column_names = extract_tables_and_columns(sql_query)
print("Table Names:", table_names)
print("Column Names:", column_names)

  9. How to extract table names and column names from a SQL query using the DuckDB library in Python?

    Description: This query focuses on using the DuckDB library to extract table names and column names from a given SQL query string in Python.

    import duckdb

def extract_tables_and_columns(sql_query):
    con = duckdb.connect(':memory:')
    result = con.execute(sql_query)
    table_names = result.description
    column_names = result.description
    return table_names, column_names

sql_query = "SELECT column1, column2 FROM table1 WHERE condition"
table_names, column_names = extract_tables_and_columns(sql_query)
print("Table Names:", table_names)
print("Column Names:", column_names)

  10. How to extract table names and column names from a SQL query using the pglast library in Python?

    Description: This query is about using the pglast library to parse and extract table names and column names from a given SQL query string in Python.

    from pglast import parse_sql

def extract_tables_and_columns(sql_query):
    parsed = parse_sql(sql_query)
    table_names = [node.name for node in parsed.tables()]
    column_names = [node.name for node in parsed.columns()]
    return table_names, column_names

sql_query = "SELECT column1, column2 FROM table1 WHERE condition"
table_names, column_names = extract_tables_and_columns(sql_query)
print("Table Names:", table_names)
print("Column Names:", column_names)

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